Since caladiums are considered tender perennials, they must be dug up in the fall and stored indoors over winter in cold climates like yours. Once their foliage yellows and begins falling over, caladiums can be carefully lifted from the ground. Place the plants in a warm, dry location for at least a couple weeks to dry out. Then, cut off the foliage, place the tubers in a netted bag or box, and cover in dry peat moss. Store the tubers in a cool, dry location. Once spring returns, you can replant outdoors. If you are growing caladiums in containers, they can be overwintered indoors.